FCC Chairman Kevin Martin's decision could remove the last regulatory hurdle in a lengthy and heavily criticized move to combine the companies, the Post said.

Aides to Martin said the FCC chief decided to give his support after the companies agreed last week to concessions intended to prevent the new company from raising prices or stifling competition among radio makers, the paper reported.

Martin is expected, as early this week, to issue an order that the FCC vote to approve the union of Washington-based XM and New York-based Sirius, his aides were cited as saying.

A spokesman for the FCC was not immediately available for comment.

The merger would bring entertainers such as Oprah Winfrey and shock jock Howard Stern under the same banner. It has been criticized as anti-competitive by the traditional radio industry and by some U.S. lawmakers.

Antitrust authorities at the Justice Department approved the deal in March after concluding it would not harm consumers. The department said satellite radio companies face stiff competition from traditional AM/FM radio, high-definition radio, MP3 players and audio delivered by mobile phones.

Under U.S. law, the FCC must determine whether a communications deal is in the overall public interest.

In the case of the XM-Sirius deal, the agency also has to decide whether to waive a rule that barred the two satellite radio companies from merging.